The stimulus role of lithium sulfate (Li₂SO₄) on the electrical and mechanical properties of poly (vinyl alcohol)-MWCNTS-based thin film composites

This study encompasses the evaluation of mechanical, and electrical properties of PVA-MWCNT-based thin film composites (TFC) in the presence of Li₂SO₄. The PVA-MWCNT-based TFC is obtained using solvent casting technique while the characterization is carried out through thermogravimetric analysis (TGA), Fourier transform infrared (FTIR), X-ray diffractometry (XRD), and scanning electron microscopy (SEM) techniques. Tensile testing techniques is used for measuring mechanical properties such as elasticity, tensile strength, elongation, hardness and fracture toughness of the PVA-MWCNT-based TFC. Additionally, the tensile strength has increased from 47.8 N.m^{− 2} to 80.0 N.m^{− 2}, whereas elongation at break has improved from 80.8 to 124.2 mm. Ac Impedance spectroscopy is applied to study the electrical properties of PVA-MWCNT-based TFC. Thermal studies via TGA shows that the addition of lithium salt has positive effect on the thermal stability of the based PVA-MWCNT-based TFC. The XRD results shows a decrease of crystallinity of PVA-MWCNTs-based TFC on the addition of lithium salts (Li₂SO₄). Subsequently, a smooth surface morphology of all the composites, bearing no holes or roughness in SEM micrograph confirmed a well dispersion of MWCNTs and Li₂SO₄ salt in PVA matrix. During Mechanical study, an increase in the value of young modulus, tensile strength, and elongation break are observed with the addition lithium salt. Ac Impedance results show an increase in conductivity of PVA-MWCNTs-based TFC. The dielectric constant, dielectric loss and dielectric tangent loss properties of the PVA-MWCNT-based TFC also enhanced with the increase in lithium salts.